An application of groundwater source protection concepts to well cluster communities

P. Richards, S. Miller, K. Green

Dans les comptes rendus d’articles de la conférence: GeoMontréal 2013: 66th Canadian Geotechnical Conference; 11th joint with IAH-CNC

Session: Groundwater Management II

ABSTRACT: A pilot study was undertaken in order to evaluate the ways in which groundwater source protection methodologies could be applied to smaller hamlet communities serviced by clusters of individual wells. The hydrogeological settings of 5 small communities were conceptualized using available water well records, geological mapping and groundwater contouring methods. Time of travel assessments were completed for the communities, and were used to establish well head protection zones. The study results provided insight into groundwater source areas which should be considered in any future community planning decisions.

RÉSUMÉ: Nous avons effectué une étude pilote en vue d™évaluer les manières dont nous pourrions appliquer les méthodes de protection des sources d™eaux souterraines dans des hameaux desservis par des grappes de puits individuels. Cela dit, nous avons conceptualisé la situation hydrogéologique de cinq petites communautés en examinant les registres de puits disponibles, en procédant à la cartographie géologique et en étudiant les courbes de niveau des nappes phréatiques. Nous avons aussi évalué le temps de cheminement de l™eau dans chacune des communautés en vue d™établir des zones de protection des têtes de puits. Les résultats de notre étude nous ont donné un aperçu des sources d™eaux souterraines dont nous devrions tenir compte dans toute décision future liée à la planification de la communauté. 1 SOURCE WATER PROTECTION Ontario™s Clean Water Act (Ministry of the Environment, 2006) sets out a framework for the development and implementation of source water protection plans for municipal drinking water supplies. Under the Act, source protection plans were developed for Ontario municipal drinking water systems focusing on a watershed-based approach. Although a majority of the source protection plans focused on large municipal systems (comprising single or multi-intake groundwater or surface water supply sources), the Ministry of the Environment made funding available to the North Bay - Mattawa Conservation Authority to investigate source water protection issues related to private well clusters (in areas not currently serviced by municipal water systems). The goal of the investigation was to determine the ways in which the source water protection methodologies could be applied to such a clustered well setting. The present work was conducted as a pilot study, and was an enhancement to work being carried out on behalf of the North Bay - Mattawa Conservation Authority by Waters Environmental Geosciences Ltd. 1.1 Well Cluster Communities In 2006, a study report on the groundwater conditions extending across the region covered by the North Bay - Mattawa Conservation Area was produced by Waterloo Hydrologic, Inc. and Tunnock Consulting Ltd. This report was completed to the standards of the 2001/2002 municipal groundwater studies program (Ministry of the Environment, 2001), and provided valuable background information for the source protection study programs which followed in subsequent years. However, the smaller hamlet communities were not studied in detail under the municipal groundwater study (Waterloo Hydrologic, Inc. and Tunnock Consulting Ltd., 2006) because there were no municipal wells in operation in these communities. The application of source protection methodologies to small communities relying on dispersed private residential wells (i.e. well clusters) was not the main focus of the Clean Water Act (Ministry of the Environment, 2006). Although well clusters are not defined explicitly in the Clean Water Act, well clusters can be considered a Type 2 System under the Act, and fit the definition of a large municipal residential system (O.Reg. 170/03, Ministry of the Environment, 2003) if they contain 6 or more individual wells on one or more properties (Safe Drinking Water Act, Ministry of the Environment, 2002). Type 2 drinking water systems are defined as existing and planned drinking water systems that are brought into the source protection area program through a resolution passed by the municipal council (Technical Rule 52, Ministry of the Environment, 2009). Therefore, the legislative framework exists to include well cluster communities in source protection planning activities. Unfortunately, at the outset of the present study, there was no formal definition of what constituted a well cluster community. A review of the existing guidelines and technical working papers within the source protection program did not provide any definition of a well cluster that would be of use in scoping the present pilot study.

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